Biological weapons control. Prospects and implications for the future

Biowarfare and bioterrorism

Bioterrorism is not only a reality of the times in which we live but bioweapons have been used for centuries. Critical care physicians play a major role in the recognition of and response to a bioterrorism attack. Critical care clinicians must be familiar with the diagnosis and management of the most likely bioterrorism agents, and also be adequately prepared to manage a mass casualty situation. This article reviews the epidemiology, diagnosis, and treatment of the most likely agents of biowarfare and bioterrorism.

Viral vectors for use in the development of biodefense vaccines

The heightened concerns about bioterrorism and the use of biowarfare agents have prompted substantial increased efforts towards the development of vaccines against a wide range of organisms, toxins, and viruses. An increasing variety of platforms and strategies have been analyzed for their potential as vaccines against these agents. DNA vectors, live-attenuated viruses and bacteria, recombinant proteins combined with adjuvant, and viral- or bacterial-vectored vaccines have been developed as countermeasures against many potential agents of bioterrorism or biowarfare. The use of viruses, for example adenovirus, vaccinia virus, and Venezuelan equine encephalitis virus, as vaccine vectors has enabled researchers to develop effective means for countering the threat of bioterrorism and biowarfare. An overview of the different viral vectors and the threats they counter will be discussed.

Biological agents with potential for misuse: a historical perspective and defensive measures

Biological and chemical agents capable of producing serious illness or mortality have been used in biowarfare from ancient times. Use of these agents has progressed from crude forms in early and middle ages, when snakes and infected cadavers were used as weapons in battles, to sophisticated preparations for use during and after the second World War. Cults and terrorist organizations have attempted the use of biological agents with an aim to immobilize populations or cause serious harm. The reasons for interest in these agents by individuals and organizations include relative ease of acquisition, potential for causing mass casualty or panic, modest financing requirement, availability of technology, and relative ease of delivery. The Centers for Disease Control and Prevention has classified Critical Biological Agents into three major categories. This classification was based on several criteria, which include severity of impact on human health, potential for delivery in a weapon, capacity to cause panic and special needs for development, and stockpiling of medication. Agents that could cause the greatest harm following deliberate use were placed in category A. Category B included agents capable of producing serious harm and significant mortality but of lower magnitude than category A agents. Category C included emerging pathogens that could be developed for mass dispersion in future and their potential as a major health threat. A brief description of the category A bioagents is included and the pathophysiology of two particularly prominent agents, namely anthrax and smallpox, is discussed in detail. The potential danger from biological agents and their ever increasing threat to human populations have created a need for developing technologies for their early detection, for developing treatment strategies, and for refinement of procedures to ensure survival of affected individuals so as to attain the ultimate goal of eliminating the threat from intentional use of these agents. International treaties limiting development and proliferation of weapons and continuing development of defense strategies and safe guards against agents of concern are important elements of plans for eliminating this threat.

Clinicians’ Knowledge, Attitudes, and Concerns Regarding Bioterrorism After a Brief Educational Program

We conducted this study to determine the knowledge, attitudes, and intended behaviors of New York City clinicians regarding bioterrorism-related diseases after a brief educational program. Data on clinicians' knowledge and attitudes toward bioterrorism and related diseases were collected using a self-administered questionnaire following a 3.5-hour educational program. Participants (n = 310, 82% response rate) reported increased confidence in recognizing symptoms of bioterrorism-related diseases (89%), in addressing patients' bioterrorism concerns (83%), and ability to treat bioterrorism victims (75%). Despite a high level of confidence in the efficacy of infection control precautions, participants' knowledge scores regarding safe work practices suggest that additional education is warranted. Educational programs are useful in enhancing the public health response to bioterrorism and its consequences.

Antibody response to a delayed booster dose of anthrax vaccine and botulinum toxoid

We evaluated the prevalence and concentration of serum antibodies 18-24 months after primary inoculation with anthrax and botulinum vaccines, and assessed the reactogenicity and immunogenicity of a significantly delayed booster dose of these vaccines. Five hundred and eight male active-duty military personnel received one, two or three inoculations with anthrax vaccine and/or botulinum toxoid in 1990/1991 in preparation for Operations Desert Shield/Desert Storm. Subjects were vaccinated with the licensed anthrax vaccine, adsorbed (AVA) and pentavalent (ABCDE) botulinum toxoid (PBT) BB-IND 3723. Anthrax protective antigen (PA) IgG antibody was measured in serum using an immunocapture enzyme-linked immunosorbent assay (ELISA). A mouse neutralization test was used to determine the titer of Clostridium botulinum type A antitoxin in serum samples. The prevalence of anti-PA IgG was 30% in individuals 18-24 months after priming with one, two or three doses of AVA. After boosting, 99% of volunteers had detectable anti-PA IgG; only two individuals failed to respond. The prevalence of antibodies against botulinum toxin type A was 28% 18-24 months after initial priming. Following boosting, 99% of volunteers had serum titers >0.02IU/ml, and 97% responded with titers > or =0.25IU/ml. Systemic reactions to booster vaccinations could not be specifically ascribed to one or the other vaccine, but were generally mild and of brief duration. Forty-five percent of volunteers reported one or more systemic reactions over the course of 7 days. Injection site reactions of any kind occurred in 25% of AVA recipients and in 16% of PBT recipients; persistence of local reactions beyond 7 days was infrequent. While the kinetics and durability of immune responses must be studied, these findings suggest that booster doses of anthrax vaccine and botulinum toxoid sufficient to stimulate a robust anamnestic response may be given at times distant from receipt of the primary inoculations.

Anthrax vaccine: immunogenicity and safety of a dose-reduction, route-change comparison study in humans

Anthrax vaccine adsorbed (AVA), an effective countermeasure against anthrax, is administered as six subcutaneous (SQ) doses over 18 months. To optimize the vaccination schedule and route of administration, we performed a prospective pilot study comparing the use of fewer AVA doses administered intramuscularly (IM) or SQ with the current schedule and route. We enrolled 173 volunteers, randomized to seven groups, who were given AVA once IM or SQ; two doses, 2 or 4 weeks apart, IM or SQ; or six doses at 0, 2, 4 weeks and 6, 12, and 18 months (control group, licensed schedule and route). IM administration of AVA was associated with fewer injection site reactions than SQ administration. Following the first SQ dose of AVA, compared to males, females had a significantly higher rate of injection site reactions such as erythema, induration and subcutaneous nodules (P<0.001). Reaction rates decreased with a longer dose interval between the first two doses. The peak anti-PA IgG antibody response of subjects given two doses of AVA 4 weeks apart IM or SQ was comparable to that seen among subjects who received three doses of AVA at 2-week intervals. The IM route of administering this aluminum hydroxide adsorbed vaccine is safe and has comparable peak anti-PA IgG antibody levels when two doses are administered 4 weeks apart compared to the licensed initial dose schedule of three doses administered 2 weeks apart. A large pivotal study is being planned by the Centers for Disease Control and Prevention to confirm these results.

Anthrax vaccine: short-term safety experience in humans

Bacillus anthracis is the major terrorist and biological warfare agent of concern to civilian and military medical planners. The licensed anthrax vaccine, adsorbed (AVA) is believed to be an effective prophylactic medical countermeasure against this threat. Our objective in this report was to expand the safety database for this vaccine by assessing data on self-reported, short-term safety of AVA during more than 25 years of use, measured by local and systemic adverse events temporally associated with the administration of AVA. A minority of AVA recipients reported systemic and injection site reactions. Females reported a higher incidence of injection site and systemic adverse events than males. Data show a difference in incidence of local reactions between lots. A prospective, randomized, placebo-controlled study to actively examine reactogenicity is needed to more completely define the extent and nature of reactions associated with receipt of AVA in humans as well as to confirm the gender lot differences in local reaction rates.

Agents of bioterrorism. Preparing for bioterrorism at the community health care level

Bioterrorism preparedness is clearly a goal for the health care community, working in concert with city, county, state, and federal public health and emergency authorities and in collaboration with law enforcement at the local and federal levels. Opening the channels of communication between all groups involved, obtaining the necessary resources, and maintaining an understanding of the potential agents and the diseases they cause will foster a smooth transition to a rational program directed at patient, personnel, and community safety.

Investigating disease outbreaks under a protocol to the biological and toxin weapons convention

The Biological and Toxin Weapons Convention prohibits the development, production, and stockpiling of biological weapons agents or delivery devices for anything other than peaceful purposes. A protocol currently in the final stages of negotiation adds verification measures to the convention. One of these measures will be international investigation of disease outbreaks that suggest a violation of the convention, i.e., outbreaks that may be caused by use of biological weapons or release of harmful agents from a facility conducting prohibited work. Adding verification measures to the current Biological and Toxin Weapons Convention will affect the international public health and epidemiology communities; therefore, active involvement of these communities in planning the implementation details of the protocol will be important.

Facing the global challenges posed by biological weapons

This review article examines the growing concern about the threat posed by the use of biological weapons by States or terrorist groups. The article analyzes the nature of the perceived risk from bioweapons, the historical attempts to control them, and the emerging policy and legal framework designed to deal with the bioweapon threat.

Anthrax vaccine. Model of a response to the biologic warfare threat

Anthrax vaccine is being administered to all 2.4 million active duty, reserve, and National Guard troops, as prophylaxis against biologic warfare. The vaccine's effectiveness in this setting may be limited. This article discusses unresolved issues of safety, with an emphasis on the need for careful surveillance of vaccines used by the military, which has sidestepped the commercial process. Also considered are ethical issues related to the development and use of military biologics, as the United States Army advances its Joint Vaccine Acquisition Program, a plan to produce more than ten vaccines specifically for biologic warfare threat, and to administer them to all military servicemembers.

Strengthening the biological weapons convention and implications on the pharmaceutical and biotechnology industry

The development, production, stockpiling, and use of biological weapons are banned by the 1972 Biological Weapons Convention (BWC). Reflecting the realities of the Cold War era in which it was negotiated, the BWC lacks means for compliance verification or enforcement. International efforts to remedy this deficiency are accelerating in the face of evidence that covert biological weapon programs are proliferating at the national and subnational levels.

Legal issues associated with antimicrobial drug resistance

An effective public health strategy against the development of antimicrobial drug resistance needs to be informed by legal as well as scientific analysis. This article describes some legal issues arising from current efforts against antimicrobial resistance and underscores the interdependence between law and public health in these efforts.